Highly radiation-resistant Al-MOF selected based on the radiation stability rules of metal–organic frameworks with ultra-high thorium ion adsorption capacity

Abstract

For the new generation of thorium-based molten salt reactors to operate in the future, irreversible adsorption of radioactive thorium ions is required. Therefore, designing highly irradiation-resistant, high-adsorption capacity porous adsorbents for the adsorptive removal of radioactive thorium ions is a great challenge. Herein, based on the radiation stability rules of MOFs (Al³⁺ metal nodes and unmodified organic ligands), we used a simple solvothermal method to synthesize an aluminum-based MOF, Al-MOF. The strong β-ray resistance with Al-MOF was confirmed by XRD and FT-IR characterization as well as adsorption isotherm experiments under β-ray irradiation with a total dose of 1000 kGy. Additionally, Al-MOF exhibits ultra-high Th(IV) adsorption capacity (1324.64 mg g⁻¹) and Th(IV) adsorption selectivity (K^Th_d/K^M_d ≥ 6 × 10³). This study provides guidance for the design of efficient MOF-based adsorbents for applications in spent fuel reprocessing and further expands the practical application of MOFs.